Blame wood-buring stoves for winter air pollution and health threats ~ Opinion



Author Michael D. Mehta, Professor, Department of Geography and Environmental Studies, Thompson Rivers University

It may be natural, but there’s nothing safe or environmentally sound about heating your home with wood.

The World Health Organization has ranked air pollution and climate change as the top health threat for 2019. One in nine deaths around the world are due to air pollution.

In Canada, air pollution kills nine times more people than automobile accidents. My own research shows that in rural British Columbia the main source of winter air pollution is residential wood burning, and that it is mostly being ignored and rarely monitored by government.

Health hazard

Wood smoke may smell good, but it is not good for you.

The main threat comes from the cocktail of tiny particles and droplets that are about 2.5 microns in diameter (also called PM2.5). Due to their size, they easily work their way into our lungs, bloodstream, brain and other organs, triggering asthma attacksallergic responsesheart attacks and stroke.

Chronic exposure to PM2.5 is linked to heart diseaselung cancer in non-smokerschronic obstructive pulmonary diseaseType II diabetes and dementia.

Wood smoke affects everyone, but children are especially vulnerable in part because their respiratory systems are under development. Pregnant women exposed to wood smoke may have children with smaller lungs, impaired immune systems, decreased thyroid function and changes to brain structure that may contribute to difficulties with self control. Children who are hospitalized for lower respiratory tract infections are more likely to have a wood stove in the house, although other factors may also play a role.

The elderly are also at risk. A recent study of people living in B.C., in Kamloops, Prince George, Courtenay and the Comox Valley, showed that wood stove pollution significantly increased the rate of heart attacks in people over 65.

And that nice smell? It comes from benzene, a carcinogen (cancer-causing substance), and acrolein.

With the dozens of toxic and carcinogenic chemicals in wood smoke, it’s inconsistent for governments to ban smoking and vaping in public places while ignoring the smoke from wood stoves and fireplaces.

Neither sustainable nor carbon neutral

Burning wood for energy releases more carbon than burning coal and it is speeding up climate warming. It also releases black carbon, a powerful short-lived pollutant, that can accelerate the melting and retreat of glaciers.

Pollution from wood fires can become trapped in a valley when warm air holds cold air close to the ground. S/V Moonrise/Wikimedia, CC BY-SA

There are alternatives. For everyday heating, mini-split air source heat pumps are an excellent option. They are often three to four times more efficient than electric baseboard heaters and can work in colder climates. For example, the community of Skidegate in Haida Gwaii placed heat pumps in every house, reducing the use of wood for home heating.

Efficient propane stoves and heaters are an excellent complement to heat pumps and can provide top-up heating on very cold days as well as backup heating during power outages.

Most regional and municipal governments in B.C. have been reluctant to deal with these issues, and tend to focus on wood stove exchange programs as the solution. Based on my current research, the vocal response by the wood-burning industry and its customers often drowns out reasoned discussion.

The B.C. Lung Association has also been a strong advocate of wood stove exchange programs. But even the cleanest, highest level of eco-certified wood stoves generate more particulate matter per hour than 18 newer diesel passenger cars — and the wood stove may be right beside you.

Citizen science is a game changer

Concerned citizens have set-up an extensive and a growing network of low-cost air quality monitors made by PurpleAir. Kamloops, for example, with a topography that tends to trap air pollution from heavy industry and residential wood burning, has 30 of these wifi-enabled, real-time sensors, as do hundreds of other communities around the world.

These monitors show a distinct and troublesome pattern. The clear “signature” of wood burning shows that many rural B.C. communities often have winter air pollution levels that far exceed those seen in larger cities like Victoria and Vancouver. Some of the sensors register air quality readings that rival bad air days in China and India. Wood smoke is creating hot spots that expose people to levels of air pollution not normally recorded by provincial air quality monitors.

Wood smoke, and the cultural and social practices that allow it to be generated without much regulation and control, operates in a vacuum where preconceptions, origin stories and strong emotions impair action. We need another narrative.

Lack of government action to deal with this problem encourages people to ignore this evidence and to underestimate the risk. Burning wood deprives people of the right to breathe clean air in their own homes, and it ultimately represents an uncontrolled form of secondhand smoke exposure with broad implications.

This article was originally published on The Conversation. Read the original article.

The Conversation

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  1. Brian Tapley on

    I agree with this assessment, even as my wood furnace is chewing it’s way through the 20th cord of firewood this week. It’s been a heavy winter for heating so far.
    I like the split systems, good idea, but like most heat pumps they don’t work well if the temperature gets much below zero. The COP drops off and one has to keep thawing the ice off the outdoor coils. They work great in Haida Gwaii I’m sure as it barely even freezes so this would be an “ideal” location for them. The government paying for them is an ever nicer idea… hear that MP and MPP and District etc.??
    I don’t think they are so good here.
    I’ve got solar hot water heat too. Trouble is it works best when you don’t actually need it because the sun is shining in your living room windows and the house is already warm. They do make the domestic hot water however and that is a plus. When I put them in I was originally going to build a greenhouse, with the collectors on top so that I’d get the use of the greenhouse and could build a large storage tank for the solar heat collected. The local building department would not allow this however, without an expensive bunch of planning amendments and such so the collectors ended up on a roof, which made them happy at the time but also rendered the large storage and greenhouse to be not part of the plan so they are only about half as good as they could have been.
    I’m getting older and thinking more each year about going back to burning oil. Much simpler, less work and none of those ashes to haul and try to spread in the forest to make the trees grow. You can’t usually smell oil smoke too!
    Personally, I love the smell of coal smoke. Coal smoke and hot grease could be a perfume to an engineer and when combined with some steam toasted hemlock sawdust in an old time sawmill… that was pretty good. However mention of coal will probably get me banished to some tropical paradise like Savarlebad or Murmansk so we shall not go with coal.
    Wood, like coal peat and camel dung, is ok in the countryside, not so good in a city but one thing we have lots of here in Muskoka is wood. We don’t have oil, propane, or coal and there are darn few camels roaming about so to all these fuels one must add the cost to get them here.
    Pretty much nothing works without electricity so maybe just add some more nuclear and use that. it is very clean, the cleanest we have now that is available 24/7. Renewable sources can’t beat this, we have the technology for cheaper and safer plants than we have now and we have the fuel and expertise to build and run them.
    Of interest would be more micro hydro plants. Virtually every waterfall or significant rapids could be generating electricity around here. The way they did the Bala plant is a textbook example of how not to do it however. There are better ways if anyone wants to think and listen, ways that benefit the local population rather than the equivalent of Swift River Energy (Bala) and even small water power plants help a lot as they can run when needed, not just when the wind blows or sun shines.

  2. Sandy Inkster on

    With the information listed in this article, one might conclude that campfires are also a very harmful contributor, especially in this area full of cottages, camps, campgrounds, parks and properties. So, the question becomes: does this article then propose to ban any type of wood burning, year round?

  3. The ideal solution: electric hot water; yes, with old-fashioned radiators. Unfortunately, a relative few can afford this alternative, and still more are offended by the appearance of radiators. Mr. Tapley was definitely headed in the right direction (to build a reservoir for his solar-heated water). I would be interested to know what objections Town Planning could possibly have to such a “sustainable” system.

    • Ryan Vallentin on

      You don’t need the radiators to have an electric hot water system, you can have a forced air furnace with an air-to-water heat exchanger. Think radiator inside furnace with air blowing across.

  4. Michael Alderson on

    This article is not up todate.
    The new wood stoves like (Pacific Energy )products have a reburn technology. This tech reduces the particulates to less the 1.3 gr/hr while almost elimatining all visual smoke coming out of the chimney and surrounding environment.
    Additionally the consumption of wood is also greatly reduced.
    There is also the Rocket Mass heater which has proven to reduce 95% -99%of all particulates. also reducing wood consumption by 80-90%

    Please do your research
    Eat healthy .stay active .be positive

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